The present invention relates to a printing device and a method for printing background images.
There are now known thermal printing devices which produce labels having a length corresponding to a message to be printed as defined by a user. Such devices operate with a supply of tape arranged to receive an image and a means for transferring an image onto the tape. In one known device, a tape holding case holds a supply of image receiving tape and a supply of an image transfer ribbon, the image receiving tape and the transfer ribbon being passed in overlap through a print zone of the printing device. At the print zone, a thermal print head cooperates with a platen to transfer an image from the transfer ribbon to the tape. A printing device operating with a tape holding case of this type is described for example in EP-A-0267890 (Varitronics Inc). In this printing device, the image receiving tape comprises an upper layer for receiving an image which is secured to a releasable backing layer by a layer of adhesive.
In another device, the construction of the image receiving tape is such that the upper image receiving layer is transparent and receives an image on one of its faces printed as a mirror image so that it is viewed the correct way round through the other face of the tape. In this case, a double-sided adhesive layer can be secured to the upper layer, this double-sided adhesive layer having a releasable backing layer.
This latter arrangement is described for example in EP-A-0322918 and EP-A-0322919 (Brother Kogyo Kabushiki Kaisha), and in EP-A-0487312 (Esselte N. V.).
Printing devices of this type also include a display means and an input means such as a keyboard for selecting characters to be printed. Selected characters are displayed on the display means and in this way a user can compose a label to be printed. When a label has been composed a print instruction is given and the printing device proceeds to print a label. Printing devices of this type also include cutting means to cut off the printed portion of the tape to enable it to be used as a label For use as a label, the releasable backing layer is removed from the upper layer to enable the upper layer to be secured to a surface by means of the adhesive layer. In this way, labels having a length and character arrangement determined by a user can be made.
Label printing devices of this type are increasingly being provided with a greater variety of images which can be printed. EP-A-600593 describes a tape printing device which has the facility to select pattern data for printing over characters. For example, the pattern data can be a shaded pattern or a framed shaded pattern.
It would be desirable to further enhance the principle facilities of a tape printing device of the aforementioned type.
According to one aspect of the invention there is provided a printing device comprising: user input means having function setting means for selectively instigating a background text state and an edit state and character selection means for selecting characters or symbols to be printed; a label memory for holding label data in the form of characters or symbols selected as background text and characters or symbols selected as foreground text; a printing mechanism for printing images based on said label data; a controller responsive to the user input means and the label data to control the printing mechanism; wherein the controller is operable to generate print data for the printing mechanism to print said selected background characters or symbols as grey shaded background.
In the described embodiment, the controller is operable to generate print data simultaneously for printing the selected background characters or symbols as grey shaded characters, and for printing the foreground text overlying the background characters. The controller generates print data on a column by column basis by generating a background print column and a foreground print column, and logically combining the background print column and the foreground print column to generate each column of print data. In the described embodiment, the logical combining operation is a logical OR action.
The printing device can include tape width selection means for selecting the width of a tape on which the images are to be printed. The tape width selection means can comprise a switch on the tape printing device which has a plurality of positions, each position denoting a particular tape width or combination of tape widths. The size of the characters selected as background text can be dependent on the width of the tape selected by the tape width selection means. In the described embodiment, if the tape width is below a certain value, no background text is printed. That is, the printing of background text is inhibited for tape widths below a certain value.
Characters for background text can be held in a font memory which in addition holds font data defining characters and symbols to be printed as foreground text. The first font data can be dot pattern data, while the second font data is compressed data. In the following, the background characters and/or symbols are referred to as so-called big font. The big font is held in a compressed format and can be generated in a normal size (for a certain range of tape widths), or a double size (for a range of larger tape widths).
The label memory can comprises a working portion which holds label data defining a label under edit, and a storage portion which holds label data defining stored labels. The label data can include background text labels which, when recalled, are used as background text to generate grey shaded background for input foreground text.
The font memory can, in addition, hold pattern data defining a plurality of selectable background patterns.
Another aspect of the invention provides a method of printing an image on an image receiving medium, the method comprising: instigating a background text state and selecting background image data; instigating an edit state and selecting foreground image data; generating successive print data columns by generating a background print column and a foreground print column and logically combining said background effect print column and foreground print column to generate each print data column; and printing said columns sequentially while moving the image receiving medium past a printing mechanism for printing said columns, wherein said background image data is printed in grey shade.
The foreground text can be printed in full black tone on the grey shaded background. The background image data can comprise selected characters and/or symbols, or can comprise pattern data selected from a plurality of background patterns.
For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made by way of example to the accompanying drawings.